JPH02245009A - Block copolymer and its composition - Google Patents

Abstract

PURPOSE:To obtain a block copolymer which can give a resin composition of excellent mechanical strengths when kneaded with PP or the like by hydrogenating a specified block copolymer to a specified degree of hydrogenation of the olefinically unsaturated bonds. CONSTITUTION:A block copolymer of a number-average MW of 10000-500000 prepared by copolymerizing 20-80wt.% polymer block, formed by polymerizing 30-100wt.% dimethyl-1,3-butadiene (e.g. 2,3-dimethyl-1,3-butadiene) with 70-0wt.% 1,3-butadiene and/or isoprene, with 80-20wt.% polymer block by polymerizing butadiene and/or isoprene is hydrogenated to a degree of hydrogenation of the olefinically unsaturated bonds >=70%.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Industrial Application Field The present invention relates to a resin composition useful for automobile interior and exterior parts, and more particularly, to a special block copolymer and a resin composition using the block copolymer. Polypropylene resin and ethylene
The present invention relates to a resin composition comprising a propylene copolymer rubber and having improved processability and mechanical strength.

b. Prior Art Compositions made of polypropylene and ethylene-propylene copolymer rubber are widely used as interior and exterior parts of automobiles.

In order to make the composition stable and excellent in processability and mechanical properties, a method of producing the composition by vulcanization under heating and melting (for example, JP-A-53-149240, JP-A-53
-149241, JP-A-56-125442, etc.) are used.

However, in the manufacturing method using only such vulcanization method,
For example, in regions with a high polypropylene content, polypropylene decomposes in the presence of peroxide, so in order to maintain physical properties, new polypropylene resin must be added before kneading is completed, or ethylene-
In areas with a high propylene content, it is very difficult to control vulcanization and there are problems in that it is difficult to obtain good processability.

Problems to be Solved by the C0 Invention The present invention is a specific block copolymer made to solve these problems in the prior art, and by using it, polypropylene resin and ethylene-propylene copolymer rubber can be produced. The object of the present invention is to provide a resin composition that exhibits excellent processability and mechanical strength over a wide range of composition ratios and can broadly meet diversifying required physical properties.

Means for solving the d1 problem As a result of intensive studies, the present inventors added a specific block copolymer to a polypropylene resin and an ethylene-propylene copolymer rubber composition, and then processed it by a dynamic vulcanization method. It has been found that the object of the present invention can be achieved by
We have arrived at the present invention.

That is, the present invention provides dimethyl-1,3-butadiene 30
20-80% by weight of a polymer block formed by polymerizing ~100% by weight and 70-0% by weight of 1,3-butadiene and/or isoprene, and a polymer block 80 formed by polymerizing butadiene and/or isoprene. ~20
% by weight and a number average molecular weight of 10,000 to 500
.,000, wherein at least 70 of the olefinically unsaturated bonds of the block copolymer are
% of the hydrogenated block copolymer, and a composition obtained by kneading the hydrogenated block copolymer with a polyolefin resin and an olefin copolymer rubber.

The block copolymer used in the present invention is dimethyl-1
, 3-butadiene and 0-70 weight % of 1,3-butadiene and/or isoprene. [obtained by anion living polymerization in a solvent using an initiator such as lithium] A block copolymer having two or more polymer blocks is obtained by hydrogenation.

Although a branched block copolymer can be obtained from these block copolymers before being hydrogenated by using a polyfunctional coupling agent, linear block copolymers are preferably used.

The monomer used is dimethyl-1,3-butadiene 1
00 to 30% by weight, 1,3-butadiene and/or isoprene 0 to 70% by weight, and butadiene and isoprene.

As dimethyl-1,3-butadiene, 1゜1-dimethyl-1,3-butadiene, 1,2-dimethyl-1,3
-butadiene, 1,3-dimethyl-1,3-butadiene, 1,4-dimethyl-1゜3-butadiene, 2,2-dimethyl-1,3-butadiene, 2,3-dimethyl-1,
Examples include 3-butadiene, but the most preferred is 2,3-dimethyl-1,3-butadiene.

The ratio of dimethyl-1,3-butadiene to 1°3-butadiene and/or isoprene in the dimethyl-1,3-butadiene polymer block is preferably 5.
0-100150-0, more preferably 80-100
/20 to 0 (polymerization %). Furthermore, between 1,3-butadiene and isoprene, 3-butadiene is preferable.

The butadiene and/or isoprene-based polymer block (hereinafter referred to as polyisoprene-based block) may be copolymerized with a small amount of other monomers in addition to butadiene and isoprene, but only butadiene and/or isoprene should be used. It is desirable to use only isoprene.

Various polymerization solvents can be used, including dimethyl-1,
In order to keep the vinyl structure of the 3-butadiene polymer block portion low, aromatic hydrocarbons are preferred, and benzene or toluene is particularly preferred.

In addition, the content ratio of each block part in the block copolymer, that is, the dimethyl-1,3-butadiene polymer block part and the polyisoprene block part is 20 to 80/80.
~20 (wt%), preferably 30~70/70
-30, more preferably 35-65/65-35, and particularly preferably both blocks have substantially the same molecular weight. In a block copolymer in which the molecular weights of both block parts are greatly different, when a hydrogenated block copolymer is added to a polymer mixture such as polyolefin, it does not migrate to the interface between both phases in the polymer mixture, and the block copolymer is hydrogenated. Since the hydrogen block copolymer alone tends to form a separate dispersed phase, its performance as a compatibility modifier is poor and undesirable.

In the production of block copolymers, organolithium-based initiators can usually be used.

As the organolithium initiator, n-butyllithium, 5
Ec-butyllithium, tert-butyllithium, etc. are used.

The polymerization may be carried out in a batch manner or in a continuous manner, and a coupling agent may be used. In order to obtain a block copolymer with a narrow molecular weight distribution and a clear structure, it is preferable to obtain a block copolymer by adding monomers sequentially without using a coupling agent in a batch process.

In the polymerization, the polymerization temperature is usually 0 to 120°C, and the polymerization time is 1
It is carried out for 0 minutes to 12 hours.

By hydrogenating the block copolymer polymerized in this way, the hydrogenated block copolymer of the present invention can be obtained.

The hydrogenation rate (hydrogenation rate) of olefinic unsaturated bonds in the hydrogenated block copolymer of the present invention is 70% or more, preferably 90% or more, and more preferably 95% or more. If the hydrogenation rate is less than 70%, the performance of the polymer as a compatibilizer will be poor and the weather resistance will also deteriorate, which is not preferable.

The hydrogenation reaction is carried out by dissolving the block copolymer in, for example, a hydrocarbon solvent, and heating the block copolymer at 20 to 150°C and 1 to 100k
It is carried out under pressurized hydrogen of g/cJ in the presence of a hydrogenation catalyst.

Hydrogenation catalysts include catalysts in which noble metals such as palladium, ruthenium, rhodium, and platinum are supported on silica, carbon, and diatomaceous earth, complex catalysts such as rhodium, ruthenium, and platinum, and organic carboxylates and organic acids such as cobalt and nickel. Catalysts consisting of aluminum, organolithium, titanium compounds such as dicyclopentadienyl titanium dichloride, dicyclopentajenyl diphenyl titanium, dicyclopentajenyl titanium ditolyl, dicyclopentajenyl titanium dibenzyl, and lithium, aluminum or A hydrogenation catalyst made of an organometallic compound made of magnesium, etc. is used.

The hydrogenated block copolymer of the present invention obtained as described above is a block copolymer having a block portion consisting essentially of polypropylene and an ethylene-propylene copolymer block portion. Therefore, by adding the hydrogenated block copolymer of the present invention to a polymer mixture consisting of polypropylene and an ethylene-propylene copolymer and heating and melt-mixing, the hydrogenated block copolymer can be modified to improve the compatibility of both types of polymers. It has an extremely excellent effect as a quality agent and can dramatically improve the physical properties of the polymer mixture.

For the purpose of use mentioned above, the pre-hydrogenated copolymer preferably has (1) a low vinyl structure and (2) a narrow molecular weight distribution.

That is, the vinyl bond content in each block is preferably 30% or less, more preferably 20% or less.

Further, the number average molecular weight of each block is preferably 5.0
00 or more, more preferably 10,000 or more, particularly preferably 20,000 to 200°000. 5,0
By making it 00 or more, the performance as a compatibility modifier is excellent. It is desirable that the molecular weight distribution be narrow, and the ratio of weight average molecule i (Mw) to number average molecule i (Mn) Mw/Mn
is preferably 1.4 or less, more preferably 1.3 or less, particularly preferably 1.25 or less.

Further, the number average molecule n of the entire block copolymer is 10.
000-500,000, preferably 20°000-3
00,000, more preferably 30°000 to 200
,000.

Furthermore, the hydrogenation rate also becomes an important factor.

When used as a compatibilizer for a blend of polypropylene and olefinic copolymer rubber, the hydrogenation rate of the block copolymer is preferably as high as possible, and hydrogenation of 95% or more is most preferred. Under such a high hydrogenation rate, the dimethyl-1,3-butadiene moiety becomes head-to-tai.
Since it has a polypropylene chain with an l structure, it has high compatibility with polypropylene, and the maximum effect can be expected with addition of a very small amount. When the hydrogenation rate is less than 95%, it is desirable to increase the amount added.

As mentioned above, when the hydrogenated block copolymer of the present invention is added to a mixture of a polyolefin such as polypropylene and an olefin copolymer rubber, it can greatly improve the compatibility between the two, resulting in a material with various excellent physical properties. A composition is obtained.

Examples of the polyolefin used in the composition include polyethylene and polypropylene, with polypropylene being preferred. The polypropylene resin is not particularly limited, but it is generally a propylene homopolymer obtained by homopolymerizing propylene using a catalyst called Ziegler-Natsuta catalyst, or propylene and a small amount of ethylene, or propylene and a carbon number of 4 to 12. A copolymer of propylene and ethylene or an α-olefin obtained by copolymerizing with an α-olefin is used.

When the above polypropylene resin is a copolymer, the proportion of the ethylene or α-olefin copolymer in the copolymer is usually 3 to 25% by weight, and it may be either a random or a block copolymer. It's okay.

Further, the melt flow rate of the polypropylene resin is preferably 0.3 to 100 g/10 minutes (230°C), more preferably 1 to 70 g/10 minutes (230°C).

In addition, these polypropylene resins may be used alone or in combination of two or more, and other olefin polymers such as low density polyethylene and high density polyethylene may be added to an extent that does not impair the physical properties, preferably 30% of the polypropylene resin. It may be added or mixed in an amount of less than % by weight.

Olefin-based copolymer rubbers include amorphous random elastic copolymers mainly composed of olefins, such as ethylene-propylene copolymer (EPM), ethylene-propyne-nonconjugated diene copolymer (EPDM), and ethylene-butadiene copolymer. be. Among these, E.P.
MSEPDM is preferred.

The Mooney viscosity of the copolymer rubber is not particularly limited, but is 10
A range of 120 to 120 is preferred.

The olefin copolymer rubber may be used alone or in a mixture of different types, and other elastic polymers such as BR, 5BRSNBR, etc. may be used to the extent that the physical properties are not impaired, preferably the olefin copolymer rubber. It may be added and mixed in an amount of about 40% by weight or less.

The composition ratio of polypropylene resin and olefin copolymer rubber in the resin composition of the present invention is usually 10 to 90% by weight of polypropylene resin and 90 to 10% by weight of olefin copolymer rubber.
Weight%. When the hydrogenated block copolymer of the present invention is added, since the hydrogenated block copolymer acts as a compatibilizer, it provides a stable phase structure over a wide range of composition ratios, but preferably Polypropylene resin 20-80% by weight, olefin copolymer rubber 8
It is desirable that the amount is in the range of 0 to 20% by weight.

In addition, the amount of hydrogenated block copolymer used is the total amount of polyolefin and olefin copolymer rubber 10
0.5 to 40 parts by weight, preferably 1 to 40 parts by weight
The amount is 30 parts by weight, more preferably 1.5 to 20 parts by weight.

In particular, in the case of a block copolymer with a hydrogenation rate of 95% or more, the amount used is such that the amount of dimethyl-1,3-butadiene is 1
0.0 to 90% by weight block copolymer.
It is preferably 5 to 6 parts by weight, 5 to 15 parts by weight for block copolymers containing 90 to 60% by weight, and 15 to 30 parts by weight for block copolymers containing 60 to 30% by weight.

The above-mentioned resin composition can be produced by kneading each of the components listed in 2 using a Brabender mixer, an extruder, a heated roll, or the like. In these kneading processes,
It is preferable to carry out crosslinking while heating and kneading in the presence of a crosslinking agent and, if necessary, a crosslinking aid.

Although each component of the composition may be kneaded simultaneously, it is also possible to first knead the olefin copolymer rubber and the hydrogenated block copolymer, and then add and knead the polyolefin.

Additionally, additives such as oils, plasticizers, antioxidants, pigments, and inorganic fillers may be appropriately blended and used.
Other polymers to the extent that the physical properties are not impaired, such as rubbery polymers such as polybutadiene rubber, dilyl rubber, acrylic rubber, or polystyrene, ABS resin, AES
It can be used by adding a resin polymer such as a resin. The proportion of these other polymers added is desirably 20% by weight or less based on 100 parts by weight of the resin composition of the present invention.

As the crosslinking agent added during kneading, sulfur, sulfur compounds, and ab compounds can also be used, but organic peroxides are particularly preferred. The organic peroxide is preferably a high-temperature decomposition type with a 1-minute half-life temperature of around 180°C;
, 5-dimethyl-25-di(t-butylperoxy)hexane, 1. .

3-bis-(t-butylperoxy-isopropyl)-
Preferred examples include benzene, 2,5-dimethyl-2,5-di(t-butylperoxy)-hexyne-3, and di-t-butyl peroxide.

The amount of organic peroxide used is usually 100% of the resin composition.
Per part by weight, preferably 0.001 to 1.5 parts by weight, more preferably 0.002 to 1.0 parts by weight,
Particularly preferably 0.005 to 0.8 parts by weight. If the amount of organic peroxide exceeds 1.5 parts by weight, gelation of the rubber portion will significantly progress, resulting in poor processability and poor appearance.

Further, as the crosslinking aid, a radically polymerizable polyfunctional monomer is preferable, and preferred examples include divinylbenzene and bismaleimide.

The amount of crosslinking aid used is usually 100% of the resin composition to be mixed.
It is preferably used in an amount of 0.001 to 10 parts by weight, more preferably 0.005 to 7 parts by weight, particularly preferably 0.01 to 5 parts by weight. It is not preferable to use more than 10 parts by weight because processability deteriorates.

In the resin composition of polyolefin and olefin copolymer rubber to which the hydrogenated block copolymer of the present invention is added, the hydrogenated block copolymer acts as a compatibilizer and forms a stable phase structure. It is sufficient that the amounts of the organic peroxide and crosslinking aid used are smaller than those used in the vulcanization of ordinary polyolefins.

The kneading temperature is 180 to 250, depending on the composition of the composition.
within the range of ℃. The kneading time is usually 5 to 20 minutes, but when using a Brabender mixer or hot roll, it is desirable to knead for 10 minutes or more after confirming that the composition is completely melted.

Examples are shown below to explain the present invention in more detail.

Examples] ~ 6, Comparative Example 1.2 Production of hydrogenated block copolymer (Data, 1) Purification, dehydrated benzene 80
0 cnt, 2,3-dimethyl-1,3-butadiene 1
00g was transferred under a stream of high-purity nitrogen, 0.2g of t-butyllithium was added, and polymerization was carried out at a polymerization temperature of 30°C for 12 hours. After confirming that the conversion rate was almost 100%, 100 g of purified and dehydrated isoprene was pumped through a monomer injection device under a stream of high-purity nitrogen, and
The stage polymerization was carried out for 12 hours. Conversion rate is almost 100%
After that, 4 cnt of purified and dehydrated methanol was added from a stopper injector under a stream of high-purity nitrogen to stop the reaction. The polymerization solution was poured into a large amount of methanol to precipitate and collect the polymer, which was then dried in a vacuum dryer at room temperature for 72 hours to obtain a polymer.

Obtained [2,3-dimethyl-1,3-butadiene]-
The isoprene block copolymer had a number average molecular weight of 80,000 and M w /Mn of 1.2 as determined by GPC analysis.

40 g of this block copolymer and 2000 g of purified and dehydrated cyclohexane were charged into a 31 autoclave under a stream of high-purity nitrogen, and nickel naphthenate: n-butyllithium: tetrahydrofuran was prepared in a separate container in advance.
1:8:20 (mole ratio) catalyst liquid was added to the olefin part 20
The amount of nickel was 1 mole per 00 mole.

Thereafter, hydrogen was introduced into the reaction system, and a hydrogenation reaction was carried out at 70°C. After controlling the hydrogenation rate using a hydrogen absorption group, the hydrogen in the system was replaced with nitrogen, and 2,6-tert-butylcresol was added as an anti-aging agent.
PHR was added. After decontamination and coagulation, the mixture was dried to obtain a hydrogenated block copolymer.

The hydrogenation rate of the obtained hydrogenated block copolymer was 93% (Sample No. 1).

Various hydrogenated block copolymers (
Sample Nos. 2 to 8) were synthesized. The results are shown in 1.

Examples 7-12, Comparative Examples 3-6 Hydrogenated block copolymer shown in Table 1 (Sample No.

1 to 8), the following polypropylene resin and ethylene-propylene copolymer rubber were heat-melted and mixed, and their physical properties were evaluated.

(1) Polypropylene resin; polypropylene manufactured by Mitsubishi Yuka Co., Ltd., trade name EX-6 (MFR
230°C - 1,8) (2) Ethylene-propylene copolymer rubber; EPDM manufactured by Nihon Gosei Rubber Co., Ltd., trade name EP-57P (Mooney viscosity 100°C = 88, iodine value i5.O) Mixed with consumed amount of polypropylene The resin, ethylene-propylene copolymer rubber, and hydrogenated block copolymer were placed in a pressure kneader (No. 11), and after kneading at 200°C for 10 minutes, a predetermined amount of peroxide and crosslinking agent were added, and the mixture was further heated at the same temperature. The mixture was kneaded for 10 minutes. The resulting resin mass was passed through a roll and formed into a sheet, which was then press-molded to form a square plate with a -side of 10 cm.The resulting resin mass was cut out with a dumbbell cutter to obtain a test piece for measuring mechanical properties.

These blending ratios and mechanical property measurement results are shown in Table 2.

During compounding, Kayahexa AD manufactured by Kayaku Nourii Co., Ltd. was used as a peroxide, and bismaleimide was used as a crosslinking aid.

From Table 2 below, it can be seen that the composition using the block copolymer of the present invention as a compatibilizer is a material with excellent mechanical strength.

When a block copolymer other than the present invention shown as a comparative example is used, or when no block copolymer is used at all, the mechanical strength is poor and it cannot be said to be a desirable industrial material.

[Effects of the Invention] The thermoplastic elastomer composition using the block copolymer of the present invention is a material with excellent mechanical strength, and is industrially suitable for interior and exterior parts of automobiles that require high quality, and It provides molded products such as various parts related to electricity and electronics, and has extremely high utility value in industry.

Patent applicant: Japan Synthetic Rubber Co., Ltd.

Claims (2)

[Claims] (1) 30-100% by weight of dimethyl-1,3-butadiene and 7% of 1,3-butadiene and/or isoprene
Polymer blocks 20 to 8 formed by polymerizing 0 to 0% by weight
0% by weight, and 80 to 20% by weight of a polymer block formed by polymerizing butadiene and/or isoprene, and has a number average molecular weight of 10,000 to 500,000, A block copolymer in which at least 70% of the olefinically unsaturated bonds of the block copolymer are hydrogenated. (2) A total of 100 parts by weight of 10 to 90% by weight of polyolefin resin and 90 to 10% by weight of olefin copolymer rubber, and 0.5 to 40 parts by weight of the hydrogenated block copolymer of claim (1). A composition obtained by kneading the following parts in the presence of a crosslinking agent.